Storage apparatus for storing cassettes for substrates and processing apparatus equipped therewith

ABSTRACT

The invention relates to a storage apparatus to store cassettes for substrates comprising: a moveable base plate constructed and arranged to hold cassettes; an outer wall provided with an opening to receive and remove the cassettes from the base plate, and a moving device constructed and arranged to move the base plate with respect to the opening. The storage apparatus is provided with a stationary sensor near the opening for detecting at least one of a presence and a correct orientation of a substrate cassette on the base plate at the opening.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

The present disclosure claims the benefit of U.S. patent application Ser. No. 15/673,110, filed on Aug. 9, 2017 and entitled “CASSETTE HOLDER ASSEMBLY FOR A SUBSTRATE CASSETTE AND HOLDING MEMBER FOR USE IN SUCH ASSEMBLY,” and U.S. Provisional Patent Application No. 62/585,283, filed on Nov. 13, 2017 and entitled “STORAGE APPARATUS FOR STORING CASSETTES FOR SUBSTRATES AND PROCESSING APPARATUS EQUIPPED THEREWITH,” which are incorporated herein by reference.

FIELD

The present invention generally relates to a storage apparatus for storing cassettes for substrates. The invention may also relate to a processing apparatus for processing substrates and provided with such a storage apparatus.

BACKGROUND

The storage apparatus may be employed in an apparatus used in the manufacture of discrete and integrated semiconductor products on semiconductor material substrates. To transport the substrates, cassettes may be used which may require a storage apparatus.

Storage apparatus to store cassettes for substrates comprising:

a moveable base plate constructed and arranged to hold a cassette;

an outer wall provided with an opening to receive and remove the cassette from the base plate, and

a moving device constructed and arranged to move the base plate with respect to the opening. On the base plate a plurality of cassettes for storing at least one semiconductor material substrate may be stored via the opening in the outer wall. Holding members may be located over and supported by the base plate to position the cassette on the base plate in the correct position.

To detect at least one of a presence and a correct orientation of a substrate cassette on the base plate at the opening, a sensor may be required. Since a large number of cassettes may be stored in the storage apparatus, a large number of sensors may be necessary to detect the presence and correct orientation of the substrate cassette on the base plate. The sensors may need a connection for power and communication with the stationary part of the storage apparatus. A cable feedthrough which allows for movement of the main plate may therefore be required. A drawback of the design with the moveable sensors on the base plates and the cable feed throughs may be that the design may become quite bulky.

BRIEF SUMMARY OF THE INVENTION

Therefore, it is an object of the invention to provide a storage apparatus with a simplified design of the sensor for detecting at least one of a presence and a correct orientation of a substrate cassette on the base plate.

Accordingly there is provided a storage apparatus to store cassettes for substrates comprising:

a moveable base plate constructed and arranged to hold a cassette;

an outer wall provided with an opening to receive and remove the cassette from the base plate, and

a moving device constructed and arranged to move the base plate with respect to the opening, wherein the storage apparatus is provided with a stationary sensor near the opening to detect at least one of a presence and a correct orientation of the cassette on the base plate at the opening.

By having the stationary sensor near the opening for detecting at least one of the presence and the correct orientation of a substrate cassette on the base plate near the opening there is no need for wiring in the moving base plate to detect the presence and correct positioning of the cassette. The design of the storage apparatus may thereby be simplified.

A processing apparatus for the manufacture of semiconductor products may be provided with a storage apparatus in accordance with the invention. Such an apparatus may enable products to be manufactured in large numbers and may be easy to maintain and/or install.

In addition to the parts necessary for processing the semiconductor substrates, the apparatus may comprise means for arranging the cassette in the storage apparatus or removing the cassette from the storage apparatus. Substrate handlers for arranging substrates in, or removing substrates from, the cassette may also be provided in the apparatus.

These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of certain embodiments having reference to the attached figures, the invention not being limited to any particular embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE FIGURES

It will be appreciated that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of illustrated embodiments of the present disclosure.

FIG. 1 shows a schematic horizontal cross section of a processing apparatus.

FIG. 2 is a partly broken away and schematic perspective view of another processing apparatus.

FIG. 3 is a partly broken away perspective view of a storage apparatus for the apparatus of FIG. 1 or 2.

FIG. 4 is a front view of a cassette holder assembly in accordance with an embodiment.

FIG. 5 is a back view of a cassette holder assembly of FIG. 1 provided with a cassette with substrates having a relatively small size according to an embodiment.

FIG. 6 is a back view of a cassette holder assembly of FIG. 1 provided with a cassette with substrates having a relatively large size according to an embodiment.

FIG. 7 is a top perspective view on a base plate for receiving the cassette and a bottom perspective view on a holding member before mounting on the base plate according to an embodiment.

FIG. 8 depicts a front view on a base plate for holding a cassette for substrates.

FIGS. 9a, 9b and 9c disclose a top, cross-sectional side and bottom view on the bar of FIG. 4 with further details of the moveable element according to an embodiment.

The figures are not drawn to scale, and particularly the dimensions in the thickness direction are exaggerated for clarity. Corresponding areas bear the same reference numerals whenever possible.

DETAILED DESCRIPTION

FIG. 1 depicts a processing apparatus 1 for processing semiconductor substrates, also designated with the term wafer. These wafers are subjected to a number of treatment steps in order to form a number of integrated circuits on the surface thereof which are later cut from the wafer and further processed.

It is usual to transport the substrates in cassettes, a number 9 of which is shown in top view in FIG. 1 in the storage apparatus 2. Storage apparatus 2 comprises a moveable base plate by having a rotary table 4 on which two to ten, e.g., six cassettes can be placed on each of three levels, so that this table 4 may, for example, contain a total of eighteen cassettes.

The storage apparatus 2 is provided with an outer wall 3 provided with an opening functioning as an in-out port for receiving and removing of the cassette from a clean room in which an atmosphere is maintained with a very low dust content. Via the in-out port 5 the cassettes 9 can be placed on the moveable base plate of the table 4.

As the figure clearly shows, the storage apparatus 2 has in cross section an at least partially regular polygonal periphery, that is, the three walls on the right in FIG. 1 form part of a regular octagon in cross section. The processes stations 10, 11 and 12 to be further described hereinafter also have in cross section an at least partially regular polygonal periphery. The stations 2, 10, 11 and 12 are embodied as separate stations which connect onto other stations at the position of the sides.

In the apparatus 1 a central station with a substrate handler 8 is provided. This substrate handler 8 can take substrates 13 out of cassettes 9 and place them in wafer carriers in the processing stations 10, 11, 12. After the treatment the substrate handler once again removes the processed substrates from the wafer carrier of the processing station and places them in a following processing station or in an empty cassette 9 rotated into position by means of the rotary main plate 4. The cassettes 9 with processed substrates 13 may be removed from the storage apparatus 2 via the in-out port 6 which may function in the same manner as in-out port 5.

Each of the treatment stations 10, 11, 12 shown in FIG. 1 may be provided with a rotary table 14 in which three compartments 15 are defined. Each of these compartments is provided with a wafer carrier 16. The rotary table 14 can be moved and arrested in three rotational positions. In each of these positions, one of the wafer carriers is accessible to the robot in the transfer station 8. After loading a wafer carrier 16 into one of the three compartments 15, the rotary table 14 is moved clockwise a third of a turn. The just filled wafer carrier is herein positioned above a lifting device 17 and below an oven. By means of lifting device 17, the filled wafer carrier is raised into the oven where processing of the wafers takes place. When the processing is completed the wafer carrier is once again moved downward into the table 14 which is then moved another third of a turn. Meanwhile the following wafer carrier 16 is filled again and can be placed into the oven using the lifting device 17. The just treated wafers can cool for a time. After a treatment cycle has once again been ended, the rotary table is again rotated through a third of a turn and the wafer carrier 16 with treated and cooled wafers is back in the starting position adjoining the transfer station 8. The treated wafers are then taken out of the wafer carrier and placed for instance in the ready-standing wafer carrier of processing station 11 or in the ready-standing cassettes 9. The operation for the processing stations 11 and 12 is in this case identical.

The storage apparatus 2 may be combined with two or only one of the processing stations 10, 11 or 12. Other processing stations may be employed instead of the processing stations 10, 11, 12. As a result of the embodiment as separate connectable units having in cross section an at least partially regular polygonal periphery wherein the units connect onto other units at the position of the side of the regular polygonal periphery, a large degree of freedom of construction of a device is possible in accordance with the desired treatments.

As further shown in FIG. 1, the substrate handler 8 is embodied with a square periphery and the storage apparatus 2 and processing stations 10, 11 and 12 each have a partially regular octagonal periphery with angles of 135 degrees and with a side of a length equal to that of the substrate handler 8. Hereby the storage apparatus 2 and processing stations 10, 11 and 12 may be connected in combination with one substrate handler 8.

However, due to the construction according to the invention another assembly is also possible. FIG. 2 shows for instance a device consisting of one storage apparatus 21 corresponding to that shown in section in FIG. 1 and two processing stations, each of which may correspond to the processing stations 10, 11 and 12. Here also a substrate handler 22 is arranged. This substrate handler comprises, as described above, a robot 25 which can take the wafers 13 out of the cassettes 9 and place them in the wafer carrier 27 of the processing stations and vice-versa. Robot 25 can be a per se known robot and is mounted on a lifting device so that the operational arm thereof can bridge the height difference between the bottom wafer in the lower cassette and the top wafer in the upper cassette 9. It is otherwise usual that the displacement of the wafers takes place successively from the lowest to the uppermost position, that is, the wafers 13 are taken out of the cassettes 9 or wafer carriers 27 beginning with the bottom one and continuing to the topmost, while these are re-placed once again in the wafer carrier or the cassettes beginning with the topmost and continuing thus to the bottom. This prevents possible dust particles falling onto the underlying wafers.

As is shown clearly in FIG. 2, each connectable station has in this embodiment a closed casing with closable passage openings in at least one of the sides in the part with the regular polygonal periphery. In this embodiment the processing stations 23, 32 each have one passage opening 26. The storage apparatus 21 is provided with three passage openings 24. The passage openings can be opened and closed using a hatch 29 which is received in guides 30 and which can be moved up and downward by means of a linear actuator, such as, for example, pneumatic cylinder 31. An inflatable seal may be incorporated in the guiding 30. In the closed situation of the hatch 29 this seal is inflated and a closely adhering seal contact is thus obtained. When the hatch 29 has to be moved the inflatable seal may be made pressureless, so that it removes itself from hatch 29. As a result, when the hatch 29 is opened, there is no or only minimal slide contact so that the danger of formation of loose dust particles, which is particularly undesirable in the environment of a device according to the invention, is very small. Also designated schematically in FIG. 2 is the wafer carrier 27 received in the rotary table 28.

FIG. 3 shows an storage apparatus according to the invention. This apparatus 35 has in cross section a wholly regular octagonal form with equal sides. Storage apparatus 35 may be provided with four passage openings 38 similar to the passage openings 24 of the unit 21 as shown in FIG. 2. The apparatus 35 may comprise a rotary table 36 in which eight cassettes 9 for wafers 13 may be placed on each of three levels. The table 36 may be driven in rotation around a vertical axis and fixed in different rotational positions using a drive device 37 accommodated in a closed compartment of the apparatus 35.

The apparatus 35 may be provided with its own gas circulation device. This comprises a central gas feed via the shaft 40 of the rotary table which leads to the inner space of a centrally disposed cylindrical filter 39. The gas supplied via shaft 40 flows in horizontal radial direction through this filter 39 in a laminar flow through the cassettes 9. Close to the outer periphery the gas flows upward and is discharged via an outlet 41 arranged in the upper portion of the storage apparatus 35. Due to the thus realized central feed of the gas, all sides of the apparatus 35 are possibly available for connection with other units. The gas circulation may be necessary for purging for maintaining a very low dust particle level in the apparatus.

FIG. 4 is a front view of a cassette holder assembly for the storage apparatus 2, 35 (in FIGS. 1 and 3) for storing cassettes 9 with substrates 13 in accordance with an embodiment. The cassette holder assembly 61 comprises a moveable base plate 63 provided to the rotary table 4, 36 of FIGS. 1 and 3).

The cassette holder 61 comprises an equal left holding member 65 a and right holding member 65 b supported by the moveable base plate 63 to position the cassette on the right R and left L respectively seen from the front F. The left and right holding members 65 a, 65 b are substantially identical to each other. Each of the holding members 65 a, 65 b are mirror symmetrical with respect to the line J through the center of the holding members from a back B to the front F.

An additional holding member in the form of a bar 66 may be provided on the base plate 63 to position the cassette. The bar 66 may be provided with a hole 68 which may be used by a sensor to sense the presence and or correct positioning of a cassette on the cassette holder 61.

Each of the holding members 65 a, 65 b may have end surfaces 67LB, 67LF, 67RB, 67RF to engage with the cassette to limit a position of the cassette in the front F to the back B direction substantially parallel to the base plate 63. Each of the holding members may have left end surfaces 67LB, 67LF and right end surfaces 67RB, 67RF. The right end surfaces 67RB, 67RF may be located at the right of the holding member 65 a, 65 b and the left end surfaces 67LB, 67LF may be located at the left of the holding member seen from the front F. The left end surfaces 67LB, 67LF and the right end surfaces 67RB, 76RF of the holding members 65 a, 65 b may be substantially parallel.

The right end surfaces 67RB, 67RF of the right holding member 65 b and the left end surfaces 67LB, 67LF of the left holding member 65 a may be arranged for engagement with a cassette 69 (see FIGS. 5 and 6). The right end surfaces 67RB, 67RF of the left holding member 65 a and the left end surface 67LB, 67LF of the right holding member 65 b may not be arranged for engagement with the cassette 9. If there is wear of the holding members on the end surfaces the position of the holding members 65 a, 65 b may be exchanged so that other end surfaces may be used.

Cassettes may be available in different sizes which may depend on the size of the substrates and the preferences of the fab owner in which the cassettes are used and the holding member may be constructed to be adaptable for the different sizes. Each of the holding members 65 a, 65 b may have at least two end surfaces defined as small cassette end surfaces 67RF, 67LF for a cassette 9 for 150 mm diameter substrates W (see FIG. 5) and large cassette end surfaces 67RB, 67LB for a cassette 9 for 200 mm diameter substrates W (see FIG. 6). The small cassette end surfaces 67RF, 67LF may be located towards the front F of the base plate 63 with respect to the large cassette end surfaces 67RB, 67LB to engage with cassettes with a relatively smaller size.

The holding members 65 a, 65 b may have side surfaces 71LF, 71LB, 71RF, 71RB to engage with the cassette 9 and limit the position of the cassette in a right R to left L direction substantially parallel to the base plate 63 and substantially perpendicular to the front F to back B direction. Two side surfaces defined as right side surfaces 71RF, 71RB and left side surface 71LF, 71LB may be provided. The right side surfaces 71RF, 71RB may be located at the right of the holding member seen from the front and the left side surfaces 71LF, 71LB may be located at the left of the holding member 65 a, 65 b seen from the front F.

The right side surfaces 71RF, 71RB of the right holding member 65 b and the left side surfaces 71LF, 71LB of the left holding member 65 a may be arranged for engagement with the cassette 9. The right side surface 71RF, 71RB of the left holding member 65 a and the left side surface 71LF, 71FB of the right holding member 65 b may be not arranged for engagement with the cassette 9.

The holding members comprise at least two side surfaces defined as small cassette side surfaces 71RF, 71LF and large cassette side surfaces 71RB, 71LB. The small cassette side surfaces 71RF, 71LF may be located towards the front F of the base plate 63 with respect to the large cassette side surfaces 71RB, 71LB to engage with cassettes 9 with a relatively smaller size (see FIG. 5). The large cassette side surfaces 71RB, 71LB may be located towards the back B of the base plate 63 with respect to the small cassette side surfaces 71RF, 71LF to engage with cassettes 9 with a relatively smaller size (see FIG. 4).

Both of the holding members 65 a, 65 b may have a side surface to engage with the cassette and limit the position of the cassette in right R to left L opposite directions. The cassette may thereby be positioned in the left to right direction by the holding members 65 a, 65 b.

The holding members 65 a, 65 b may be detachably secured to the base plate 63 by means of a fastener, e.g., a threaded fastener, such as a bolt 75 through a slotted hole 77. The slotted hole 77 may have a direction perpendicular to a line from the front F to the back B for adjustment of the position of the holding member 65 a, 65 b on the base plate 63.

FIG. 7 is a top perspective view on the moveable base plate 3 for receiving the cassette and a bottom perspective view on a right holding member 65 b for mounting on the base plate 63. FIG. 7 may show the slotted hole 77 with a direction perpendicular to the line J from the front F to the back B of the member 65 b. The holding member 65 b may be provided with elongated bars 79, 81 which fit in a guide slot 83 and/or a positional slot 85 provided to the base plate 63. Two guide elongated bars 79 may be smaller than the two guide slots 83 in a direction perpendicular to the line J from the front F to the back B so as to allow the holding member 65 b to be adjustably secured and guided in that direction on the base plate 63.

One positional elongated bar 81 may be the same size as the positional slot 85 in a direction substantially perpendicular and a direction substantially parallel to the line J from the front F to the back B. The positional elongated bar 81 and the positional slot 85 may fix the portion of the holding member on the base plate 63 in the left to right and front to back direction if the holding member 65 b is mounted on the base plate 63.

For cassettes that have a size that may deviate a little from the standard size cassettes the distance between the holding members 65 a, 65 b may need to be adjusted a little. For small adjustments in the distance between the holding members 65 a, 65 b in the left to right direction the positional elongated bar 81 may be (partially) removable. For example, the top of the bar 81 may be cut off so as to allow the holding member 65 b to be adjustably secured in left to right direction on the base plate 63. The guide elongated bars 79 which may be smaller than the guide slot 83 in the left to right direction allow the holding member 65 b to be adjustably secured in that direction. In the front to back direction the guide elongated bars 79 may still fix the holding member 65 b on the base plate 63. By means of a fastener, such as bolt 75 (of FIG. 4), engaging with threaded hole 89 through the slotted hole 77, the holding members may be secured.

As shown in FIG. 7 the holding member 65 b may be mirror symmetrical with respect to the line J through a center of the holding member from the front F to the back B. The symmetry in the design of the holding members 65 a, 65 b may assure that the same holding member 65 a, 65 b may be used on the right as the left on the base plate 63.

The holding member 65 a may comprise at least two, for example, four, substantially parallel end surfaces 67LB, 67LF, 67RB, 67RF (see FIG. 4). Two end surfaces may be right end surfaces 67RB, 67RF located at the right of the holding member seen from the front F and the other two end surface may be left end surfaces 67LB, 67LF located at the left of the holding member seen from the front. The end surfaces 67LB, 67LF, 67RB, 67RF may be substantially parallel to each other. Further the holding member 65 a may comprise at least two, for example, four, substantially parallel side surfaces 71LF, 71LB, 71RF, 71RB. Two side surfaces may be right side surfaces 71RF, 71RB located at the right of the holding member and the other two side surfaces may be left side surfaces 71LF, 71LB located at the left of the holding member seen from the front. The side surfaces may be substantially parallel to each other.

The side surfaces of the holding member 65 a may be perpendicular to the end surfaces. The side surface may be intersecting with an end surface. The holding member 65 a may have at least one guide surface 87 bordering with side and/or end surfaces. The guide surface 87 may have an angle between 15 to 75 degrees with the end or side surface.

The holding member 65 a may be provided with a slotted hole 77 for the fastener and wherein the slotted hole 77 has a direction perpendicular to a line from the front F to the back B of the holding member. The holding member 65 a may be provided with at least one elongated bar extending downward from the bottom surface of the member.

The holding members 65 a, 65 b may be injection molded. The holding member may comprise a polymer. For example, the holding member may comprise an acrylonitrile butadiene styrene material because of its strength and flexibility.

The holding member 65 a, can be readily manufactured by virtue of the symmetry between the left and the right side seen from the front F. It is also easier to use because there only the need to use one fastener, e.g., bolt 75 to mount the holding member 65 a on the base surface 63.

The holding member may be made from plastics or metals. The metal may be aluminum or steel. The plastic may be acrylonitrile butadiene styrene (ABS), polypropylene (PP) or polyethylene (PE). These materials may have a low coefficient of friction as well as other favorable properties, such as a good process ability. In addition, the material may be stable with respect to cleaning agents so that it can be properly cleaned.

The dimensions of the cassette holder 61 may be adapted to the dimensions of the cassette 9, which is a box-shaped body, with a front side which is open, the dimensions of which may be determined by the number and the diameter, for example, 200 mm, of the substrates W to be arranged therein. The base plate 63 may have a thickness between 0.2 and 4 mm, preferably between 0.3 and 3 mm and may be made from steel provided with holes to secure the cassette holders 65 a and 65 b to the apparatus of which the cassette holder 61 forms part.

The height dimension of the cassette holder members 65 a, 65 b may be 5 to 25 mm. For the cassette holders 65 a and 65 b a polymer, such as acrylonitrile butadiene styrene, polypropylene or polyethylene may be used which may have the advantage that, during operation, no metal or dust particles are formed which may be detrimental to a production process of, for example, ICs. Further materials that may be used for the cassette holders 65 a and 65 b may be aluminum or steel.

The cassette holder may be used in an apparatus for processing semiconductor substrates to transport the substrates to and from the apparatus. In such an apparatus, for example, a high-temperature furnace, a reaction chamber may be used to create fine dimension structures, such as integrated circuits, on a semiconductor substrate.

FIG. 8 depicts a front view on a moveable base plate 63 for holding a cassette for substrates in a storage apparatus 2 (of FIG. 1). The cassette 9 that is shown is held by the cassette holder of a lower moveable base plate (not depicted). The storage apparatus is provided with an outer wall provided with an opening 5, 6 for receiving and removing of the cassette 9 from the moveable base plate.

A moving device constructed and arranged for moving the base plate and the cassettes thereon may be provided. For example, in the form of the drive device 37 (e.g., rotational motor) in FIG. 3. The moving device may move the cassette on the base plate 63 towards or away from the opening.

The storage apparatus 1 may be provided with a stationary sensor 91 (see FIG. 8) near the opening for detecting at least one of a presence and a correct orientation of a substrate cassette on the moveable base plate 63 at the opening. The sensor 91 may be mounted on the inside of the outer wall of the storage apparatus or it may be mounted on a stationary frame part of the apparatus. The sensor 91 may be an optical sensor for optically detecting at least one of a presence and a correct orientation of a substrate cassette on the base plate 63. The base plate 63 may have a movable element 93 positioned to be contacted and moveable by said cassette when said cassette is placed in a correct orientation on said moveable base plate 63.

An indicator 95 may be moveable by the moveable element 93 for indicating that said cassette is present in said correct orientation. The indicator 95 may be constructed and arranged within a viewing angle of the optical sensor 91 for indicating the presence and correct orientation of a substrate cassette on the base plate to the optical sensor. The indicator 95 may be a reflective device, such as a mirror reflecting a radiation beams from the sensor 91 back to the sensor 91. The (optical) sensor 91 may have a radiation source for directing a beam of radiation (e.g., a laser beam of 640 nm) towards the mirror and a sensor to detect a reflection of the radiation beam. Since the base plate 63 is moveable and the moveable element 93 and indicator 95 are connected to the base plate they may be moveable as well. The sensor is stationary and the storage apparatus may be constructed and arranged that different indicators 95 may be moved in front of the sensor 91 by movement of the base plate 63 near the in-out port. This may have the advantage that only one sensor 91 is necessary to measure the presence and/or correct placement of cassettes on a plurality of base plates. Further there may be no need to provide electric cables to the moveable components of the storage apparatus since all the active components are provided to the stationary parts of the storage apparatus. The moveable base plate is only provided with passive components, such as the moveable element 93 and indicator 95.

FIGS. 9a to 9c disclose a top, cross-sectional side and bottom view on the bar 66 of FIG. 4 with further details of the moveable element 93 according to an embodiment. The movable element 93 may have a pivotable arm 97 and the bar 66 may be provided with a pivot 99 for pivotably mounting said pivotable arm 97 underneath the base plate 63. The indicator 95 may be provided on one end of said arm, said indicator being moveable upon pivoting of said arm indicating that said cassette is in said correct orientation. The pivotable arm may have a counterweight 98 and a stop on the other end of the arm, the stop limiting the movement of said moveable element and the counterweight pushing the moveable element against the cassette. The base plate 63 may have a hole and said movable element 93 may have a pin 100 for cooperation with the cassette and moveably configured in said hole. The bar 66 may be provided with a hole 68 and the pin may be moveable through the hole. The bar may be partly configured and arranged within an opening of the base plate 63. In this configuration the moveable element 93 may be provided at a lower side of the base plate 63.

The storage apparatus may be provided with walls 70, 72, (see FIG. 4) extending upward from the baseplate 63 leaving one side open at the front F for access to the base plate 63 with cassettes. A wall 72 opposite the open site may be provided with holes for purging the cassettes, so as to remove particles from the cassettes. The baseplate may have a horizontal plane for receiving the cassettes and the apparatus may be constructed and arranged with the baseplate moveable rotationally in a horizontal direction around a vertical axis of rotation. The walls may be extending upward from the baseplate 63 and defining a isosceles trapezoid shape on the base plate.

The walls 70, 72, and the base plate 63 may be constructed with sheet metal provided with L shaped slotted holes or straight slotted holes. The walls 70, 72, and the base plate 63 may also be provided with L shaped lips. The L shaped lips may be fitting in the L shaped slotted holes or straight slotted holes. After bending of the lip sticking through the L shaped slotted holes or the straight slotted holes a secure connection between the walls 70, 72, and the base plate 63 may be provided. By providing this secure connection multiple times between each of the walls 70, 72, and between at one or each of the walls 70, 72 and the base plate 63 a rigid construction of the carousel is created with simply using sheet metal.

The optical sensor 91 may be a camera constructed and arranged to have a cassette on the base plate 63 near the opening at the in-out port within a viewing angle of the camera for detecting at least one of a presence and a correct orientation of a substrate cassette on the moveable base plate.

The storage apparatus 2 (of FIG. 1.) may have a computer operable connected with the camera and provided with a processor and a memory, wherein the memory is provided with machine vision software for detecting at least one of a presence and a correct orientation of the substrate cassette on the base plate.

The storage apparatus 2 may be part of the processing apparatus 1 for processing substrates and may have a processing device for processing substrates. A substrate handler may be provided for moving substrates from the cassettes to the processing device and for moving the substrates from the processing device to the cassettes after processing. The processing device may have a reactor with a reaction chamber for processing a plurality of substrates.

Several substrates, such as silicon wafers, may be placed on a substrate rack or boat inside the reactor. Alternatively, a single substrate may be placed on a substrate susceptor inside the reactor. Both the substrate and the rack or boat may be heated to a desired temperature. In a typical substrate treatment step, reactant gases are passed over the heated substrate, causing the deposition of a thin layer of the reactant material or reactants of the gases on the substrate.

A series of such treatment steps on a substrate is called a recipe. If the deposited layer has the same crystallographic structure as the underlying silicon substrate, it is called an epitaxial layer. This is also sometimes called a monocrystalline layer because it has only one crystal structure. Through subsequent deposition, doping, lithography, etch and other processes, these layers are made into integrated circuits, producing from tens to thousands or even millions of integrated devices, depending on the substrate size and the circuits' complexity.

Various process parameters are carefully controlled to ensure the high quality of the resulting layers. One such critical parameter is the substrate temperature during each recipe step. During CVD, for example, the deposition gases react within particular temperature windows and deposit on the substrate. Different temperatures also result in different deposition rates.

The particular implementations shown and described are illustrative of the invention and its best mode and are not intended to otherwise limit the scope of the aspects and implementations in any way. Indeed, for the sake of brevity, conventional manufacturing, connection, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and/or physical couplings between the various elements. Many alternative or additional functional relationship or physical connections may be present in the practical system, and/or may be absent in some embodiments.

While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. For example, as described in the following numbered clauses:

1. A cassette holder assembly for holding a cassette for storing at least one semiconductor material substrate in an interior space accessible from a front end of the cassette, the cassette holder assembly comprising:

a base plate for receiving the cassette; and,

a right and a left holding member supported by the base plate to position the cassette on the right and left respectively seen from the front; wherein the right and left holding members are substantially identical to each other.

2. The cassette holder assembly according to clause 1, wherein each of the holding members are mirror symmetrical with respect to a line through the center of the holding member from a back to the front.

3. The cassette holder assembly according to clause 1, wherein each of the holding members has at least two end surface to engage with the cassette to limit a position of the cassette in the front to the back direction substantially parallel to the base plate, the at least two end surfaces comprising at least one right surface and at least one left end surface whereby the right end surface is located at the right of the holding member and the left end surface is located at the left of the holding member seen from the front.

4. The cassette holder assembly according to clause 3, wherein the right end surface of the right holding member and the left end surface of the left holding member are arranged for engagement with the cassette.

5. The cassette holder assembly according to clause 4, wherein the right end surface of the left holding member and the left end surface of the right holding member are not arranged for engagement with the cassette.

6. The cassette holder assembly according to clause 3, wherein each of the holding members has at least four end surfaces to engage with the cassette to limit a position of the cassette in a front to back direction substantially parallel to the base plate, a small cassette end surface and a large cassette end surface at each of the right and the left side of the cassette, whereby the small cassette end surface is located towards the front of the base plate with respect to the large cassette end surface to engage with cassettes with a relatively smaller size.

7. The cassette holder assembly according to clause 1, wherein each of the holding members has a side surface to engage with the cassette and limit the position of the cassette in a right to left direction substantially parallel to the base plate and substantially perpendicular to the front to back direction.

8. The cassette holder assembly according to clause 7, wherein each of the holding members comprises at least two side surfaces, comprising a right side surface and a left side surface wherein the right side surface is located at the right of the holding member and the left side surface is located at the left of the holding member seen from the front.

9. The cassette holder assembly according to clause 8, wherein the right side surface of the right holding member and the left side surface of the left holding member are arranged for engagement with the cassette.

10. The cassette holder assembly according to clause 9, wherein the right side surface of the left holding member and the left side surface of the right holding member are not arranged for engagement with the cassette.

11. The cassette holder assembly according to clause 7, wherein each of the holding members comprise at least two side surfaces comprising a small cassette side surface and a large cassette side surface whereby the small cassette side surface is located towards the front of the base plate with respect to the large cassette side surface to engage with cassettes with a relatively smaller size.

12. The cassette holder assembly according to clause 1, wherein both of the holding members have a side surface to engage with the cassette and limit the position of the cassette in right to left opposite directions.

13. The cassette holder assembly according to clause 1, wherein at least one of the holding members is detachably secured to the base plate by means of a fastener through a slotted hole and wherein the slot has a direction perpendicular to a line from the front to the back.

14. The cassette holder assembly according to clause 1, wherein the holding member is provided with at least one elongated bar extending from the bottom surface of the holding member and constructed to fit in a slot provided to the base plate.

15. The cassette holder assembly according to clause 14, wherein the at least one elongated bar is smaller than the slot in a direction perpendicular to a line from the front to the back so as to allow the holding member to be adjustably secured in that direction.

16. The cassette holder assembly according to clause 14, wherein the at least one elongated bar is the same size as the slot in a direction substantially perpendicular to a line from the front to the back and is at least partially removable so as to allow the holding member to be adjustably secured in that direction.

17. A holding member to position a cassette for storing at least one semiconductor material substrate on a base plate in a cassette holder assembly, wherein the holding member has a front and a back and is substantially mirror symmetrical with respect to a line through a center of the holding member from the front to the back.

18. The holding member according to clause 17, wherein the holding member comprises: at least two substantially parallel end surfaces whereby one end surface is a right end surface located at the right of the holding member and another end surface is a left end surface located at the left of the holding member seen from the front; and, at least two substantially parallel side surfaces whereby one side surface is a right side surface located at the right of the holding member and another side surface is a left side surface located at the left of the holding member seen from the front.

19. The holding member according to clause 18, wherein the side surfaces are perpendicular to the end surfaces and at least one of the side surfaces intersects with at least one of the end surfaces.

20. The holding member according to clause 17, wherein the holding member is provided with a slotted hole for a fastener and wherein the slot has a direction perpendicular to a line from the front to the back of the holding member.

21. The holding member according to clause 17, wherein the holding member is provided with at least one elongated bar extending from the bottom surface of the holding member.

22. The holding member according to clause 17, wherein the holding member comprises an injection molded polymer material.

It is to be understood that the configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. Thus, the various acts illustrated may be performed in the sequence illustrated, in other sequences, or omitted in some cases.

The subject matter of the present disclosure includes all novel and nonobvious combinations and sub combinations of the various processes, systems, and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof. 

What is claimed is:
 1. A storage apparatus to store cassettes for substrates comprising: a moveable base plate constructed and arranged to hold cassettes; an outer wall provided with an opening to receive and remove cassettes from the base plate; and, a moving device constructed and arranged to move the base plate with respect to the opening, wherein the storage apparatus is provided with a stationary sensor near the opening to detect at least one of a presence and a correct orientation of the cassettes on the base plate at the opening.
 2. The storage apparatus according to claim 1, wherein the sensor is an optical sensor to optically detect the presence and the correct orientation of the cassettes on the base plate.
 3. The storage apparatus according to claim 2, wherein the base plate comprises: a movable element positioned to be contacted and moveable by a cassette when said cassette is present in the correct orientation on said base plate; and an indicator being moveable by the moveable element and indicating that said cassette is present in said correct orientation, wherein said indicator is within a viewing angle of the optical sensor to indicate the presence and correct orientation of the cassette on the base plate to the optical sensor.
 4. The storage apparatus according to claim 3, wherein the movable element comprises a pivotable arm and the base plate is provided with a pivot to pivotably mount said pivotable arm to the base plate.
 5. The storage apparatus according to claim 4, wherein the pivotable arm comprises an indicator, said indicator being moveable upon pivoting of said arm indicating that said cassette is in said correct orientation.
 6. The storage apparatus according to claim 5, wherein the pivotable arm comprises a counterweight to push the moveable element against the cassette.
 7. The storage apparatus according to claim 3, wherein said base plate is provided with a hole therein, and said movable element comprises a pin to cooperate with the cassette and moveably configured in said hole.
 8. The storage apparatus according to claim 3, wherein said moveable element comprises a stop, said stop limiting the movement of said moveable element.
 9. The storage apparatus according to claim 3, wherein the moveable element is provided at a lower side of the base plate.
 10. The storage apparatus according to claim 3, wherein the indicator comprises a reflector and the optical sensor comprises a radiation source to direct a beam of radiation towards the reflector and a sensor to detect a reflection of the radiation beam.
 11. The storage apparatus according to claim 1, wherein the baseplate is provided with holding members to position the cassettes on the base plate.
 12. The storage apparatus according to claim 1, wherein walls are provided to the base plate extending upward from the baseplate leaving one side open for access to the base plate.
 13. The storage apparatus according to claim 12, wherein a wall opposite the open side is provided with holes to purge the cassettes.
 14. The storage apparatus according to claim 12, wherein the walls define an isosceles trapezoid shape on the base plate.
 15. The storage apparatus according to claim 1, wherein the baseplate comprises a plurality of areas to hold the cassettes.
 16. The storage apparatus according to claim 1, wherein the baseplate has a horizontal plane for receiving the cassettes and the apparatus is constructed and arranged with the baseplate moveable in a horizontal direction.
 17. The storage apparatus according to claim 1, wherein the optical sensor is a camera constructed and arranged to have the cassettes on the base plate near the opening within a viewing angle of the camera to detect at least one of the presence and the correct orientation of the cassettes on the base plate.
 18. The storage apparatus according to claim 17, wherein the apparatus is provided with a computer operable connected with the camera and provided with a processor and a memory, wherein the memory is provided with machine vision software for detecting at least one of the presence and the correct orientation of the cassettes on the base plate.
 19. Processing apparatus for processing substrates comprising: a storage apparatus to store cassettes according to claim 1; a processing device to process substrates; and, a substrate handler constructed and arranged to move substrates from the cassettes to the processing device and to move the substrates from the processing device to the cassettes after processing.
 20. The processing apparatus for processing substrates according to claim 19, wherein the processing device comprises a reactor with a reaction chamber for processing a plurality of substrates. 